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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Separação espermática pré refrigeração do sêmen equino / Sperm separation for cooling of equine sperm

Pessoa, Gilson Antonio January 2016 (has links)
As biotécnicas da reprodução na espécie equina avançaram na última década, tanto em conhecimento agregado por pesquisas como também pela demanda do mercado. No entanto, na espécie equina machos com subfertilidade são diagnosticados frequentemente com elevado número de espermatozoides com alterações morfológica e/ou imóveis. A utilização apenas de células viáveis para realizar o processo de resfriamento busca evitar perda de material (diluente) e produção de metabólitos tóxicos aos espermatozoides viáveis. O objetivo deste estudo foi utilizar a separação espermática (lã de vidro e centrifugação com Androcoll®) pré-resfriamento para incrementar a viabilidade do sêmen de garanhões pôneis refrigerados a 5ºC durante 48h. Os parâmetros motilidade, funcionalidade de membrana (HOST), viabilidade espermática (CFDA/PI), atividade mitocondrial e morfologia espermática foram avaliados no sêmen fresco e refrigerado (24 e 48h). A utilização da filtração por lã de vidro ou Androcoll® pré-resfriamento do sêmen equino selecionou espermatozoides com maior motilidade, funcionalidade de membrana, viabilidade espermática e atividade mitocondrial. Adicionalmente, a filtração por lã de vidro proporcionou refrigerar sêmen com elevado número de células morfologicamente normais sem perdas significativas de espermatozoides pelo processo de filtração. Tanto a técnica de lã de vidro como a centrifugação com Androcoll® mostraram-se eficientes em separar ejaculados com maior viabilidade para o resfriamento. Já a técnica de lã de vidro apresenta-se como uma técnica de baixo custo e de fácil execução para ser aplicada tanto para pequenos, ou grandes volumes de sêmen. / The reproduction biotechnologies in equine species have advanced in the last decade both in aggregate knowledge by research as well as the market demand. However, it in the equine species often with male subfertility where the ejaculate has a high number of sperm with morphological and / or property changes. The use of only viable cells to perform the cooling process seeks to avoid loss of material (diluent) and production of toxic metabolites to viable sperm. The aim of this study was to use the sperm separation (glass and spin wool with Androcoll®) pre-cooling to increase the viability of semen chilled ponies stallions at 5 ° C for 48 hours. We evaluated the motility parameters, membrane functionality (HOST), sperm viability (CFDA / PI), mitochondrial activity and morphology in fresh and chilled semen (24 and 48h). The use of filtration glass wool or Androcoll® pre-cooling of equine semen selected sperm with higher motility, functionality membrane, sperm viability and mitochondrial activity. In addition to filtration through glass wool afforded cooling semen with a high number of morphologically normal cells without significant losses of spermatozoids the filtration process. Both glass wool technique as centrifugation with Androcoll® were efficient in separating ejaculated more viability for cooling. Already glass wool technique presents itself as a low cost and simple technique to be applied to both small or large volumes of semen.
212

Undersökning av isoleringsmaterial ur energi- och miljösynpunkt : - en jämförelse av olika isoleringsmaterial för ett bostadshus i Sverige

Karlsson, Caroline January 2017 (has links)
Byggnader står för cirka 36% av koldioxidutsläppen och 40% av energianvändningen. I Sverige står hushållen för cirka 23 % av den totala energianvändningen. Valet av isoleringsmaterial är en bidragande faktor för att kunna minska energianvändningen i hushållen samt att dämpa påverkan på miljön. Därför viktigt att välja ett isoleringsmaterial som bidrar till lägre koldioxidutsläpp, är gjort på förnyelsebara material och som går att återvinna/återanvända.   Moderna Trähus är ett småhusföretag med visionen att bygga moderna trähus med så låg energianvändning och påverkan på miljön som möjligt. Den isolering som företaget använder just nu är stenull och de vill även kunna erbjuda ett miljövänligare alternativ till sina kunder.   De material som jämförs med stenullen är cellulosafiber (både skivor och lösull), träfiber och linull. De aspekter som undersöks för respektive material är väggens U-värde (samma väggtjocklek), byggnadens specifika energianvändning, koldioxidutsläpp, andra miljödata samt isoleringens kostnad.   Resultaten visar att alla material har samma U-värde och specifika energianvändning, medan träfiber och cellulosa har lägst koldioxidutsläpp. Kostnadsmässigt är stenullen och cellulosa – lösull billigast. Cellulosa – lösull är det bästa materialet  när miljö, energi och kostnad jämförs tillsammans. / Buildings account for about 36% of carbon dioxide emissions and 40% of energy use. In Sweden, households account for about 23% of total energy use. Valuation of insulation materials is a contributing factor in reducing energy consumption in households as well as dampening environmental impact. It is therefore important to choose an insulation material that contributes to lower carbon dioxide emissions, that is made of renewable materials and which can be recycled / reused.   Moderna Trähus is a small house building company with the vision to build modern wooden detached houses with as low energy consumption and environmental impact as possible. The insulation the company currently uses is stone wool and they also want to offer a more environmentally friendly alternative to their customers.   The materials that are compared to the stone wool are cellulose fiber (both slabs and bulks), wood fiber and flax. The aspects examined for the respective materials are the wall's U-value (same wall thickness), the building's specific energy use, carbon dioxide emissions, other environmental data and the cost of the insulation material.   The results show that all materials have the same U-value and specific energy use, while wood fiber and cellulose have the lowest carbon dioxide emissions. Costwise, stone wool and cellulose are the cheapest. Cellulose are the best material when environmental-, energy- and cost aspects are compared together.
213

Lerstensskiva med armering av fårull : Undersökning av böjhållfasthet, ånggenomsläpplighet, brandtålighet,värmekonduktivitet och praktisk användning.

Edkvist, Kristin, Powell, Linnéa January 2017 (has links)
The focus of this study is aimed at the traditional building material; clay, together withsheep’s wool to act as reinforcement. The combination of the two materials created thebasis for an alternative board material. Soil-based building materials were used to alarge extent in the past. The oldest clay houses found were built as early as 8000 yearsBC. During the Middle Ages in Central Europe, soil and clay were used as fillers in timberframe structures. As new building materials evolved, clay based building methodshave suffered a more secluded position in the western world. New building materialshave caused the characteristics of traditional building materials to be forgotten. Sheep’swool, unlike clay, has previously not been classified as a building material, but ismostly used for textiles. Sheep are bred generally for two purposes; meat productionand wool production. The wool that comes from sheep that are in the meat productionbecomes a by-product that is usually reckoned as waste.The study presented below involves a product development of a board material containingclay and sheep’s wool. Nine different compositions were made in different series.Focus on the three different series was places on variety of sheep’s wool, amountof sheep’s wool and the viscosity of the clay. The manufacturing of the product wasmade by hand with own thought out and manufactured aids.The lack of aggregated material properties complicates the use of clay and sheep’swool. A performance based declaration and the CE marking of a product are requiredfor a building material to become an accepted product in the construction market.Building engineering research was carried out in the laboratory environment, and basedon standardized methods calculations were made on the Clay-wool board such as flexuralstrength, vapour permeability, thermal conductivity, fire resistance and practicaluse.The result shows that the Clay-wool board is comparable to other board materials. Thetechnical characteristics of the Clay-wool board regarding flexural strength reportedvalues between 118 N and 550 N, depending on the composition of clay and wool. Allthe boards showed that the point of breaking was viscous, since the wool held the clayslabs together. When calculation vapour permeability, the result showed values between2,289 x 106 m2/s and 3,571 x 106 m2/s.The thermal conductivity was measured on one single board, the one containing thelargest amount of wool, where the value was established to 0,218 W/m*K. It was noticedthat the thermal conductivity increased when wool was clay–dipped. / Denna studie fokuserar på det traditionella byggmaterialet lera tillsammans medfårull som ska agera som armering. Kombinationen av de två materialen skapadegrunden för ett alternativt skivmaterial. Jordbaserade byggmaterial användes förri tiden i stor utsträckning. De äldsta lerhusen som hittats är byggda så tidigt sompå 8000 – talet f.Kr. I medeltidens Centraleuropa användes jord och lera till utfackningari ramverkskonstruktioner av trä. I takt med att nya byggmaterial utvecklatsfick lerbaserade byggmetoder en undanskymd ställning i västvärlden.Nya byggmaterial har gjort att det traditionella byggmaterialets egenskaper generellthar glömts bort. Fårull har tidigare inte klassats som ett byggmaterial, liktlera, utan används till största del till textilier. Får avlas generellt för två syften;köttproduktion och ull produktion. Ullen som kommer från får i köttproduktionenblir en biprodukt som vanligen räknas som avfall.Studien som presenteras omfattar en produktutveckling av ett skivmaterial innehållandelera och fårull. Nio olika kompositioner gjordes i tre olika serier. Fokuspå de tre olika serier lades på fårullssort, ullmängd och lerviskositet. Tillverkningav lerullsskivorna gjordes för hand med egna uttänkta och tillverkade hjälpmedel.Bristen på sammanställda materialegenskaper komplicerar användningen av leraoch fårull. Det krävs en prestandadeklaration och CE-märkning av en vara för attett byggmaterial ska bli en accepterad produkt på byggmarknaden. Byggnadstekniskforskning gjordes i laboratorisk miljö och utifrån standardiserade metoderhar beräkningar gjorts på lerullskivorna gällande, böjhållfasthet, ånggenomsläpplighet,värmekonduktivitet, brandtålighet samt praktisk användning.Resultatet visar på att lerullsskivan är jämförbar med andra skivmaterial. Lerullsskivornastekniska egenskaper gällande böjhållfasthet redovisade värden mellan118 N och 550 N, beroende på komposition av lerullsskiva. Alla skivor visade påsega brott, eftersom ullen höll ihop lerullsskivorna. Vid beräkning av ångpermeabilitetvisade resultaten på värden mellan 2,289 x 106 m2/s och 3,571 x 106m2/s. Värmeledningsförmågan beräknades endast på lerullsskivan med störstmängd ull, där värdet blev 0,218 W/m*K. Det uppdagades att värmeledningsförmåganökade när ullen dränktes i lervälling.
214

Production et consommation textiles à Tours aux XVe et XVIe siecles : Approche archéologique / Textile production and consumption in Tours at 15th and 16th centuries : archaeological approach

Henri, Delphine 18 December 2015 (has links)
La découverte à Tours de plus de six mille fragments de textiles dans la même fosse, à l’extérieur du rempart qui longe la berge de la Loire (site 69 « place Anatole France »), a permis d’étudier tout le processus du travail textile, du fil au rejet. La quasi-totalité des éléments examinés sont en drap de laine, grande industrie en Europe aux 15e – 16e siècles. Tout comme pour les soieries, moins bien conservées, l’étude s’est attachée à déterminer s’il s’agit de produits tourangeaux. Le traitement des draps de laine, augmentant leur résistance, a permis l’observation des formes, dont quelques pièces de vêtements isolées. Les pièces vestimentaires ont été découpées pour produire lacets et chausses avec une fréquence qui incite à voir dans le rejet la vidange d’un atelier de fripier. Ce corpus et l’analyse de chartes concernant la ville de Tours ouvrent un aperçu de la vie quotidienne dans une capitale de la fin du Moyen Âge, où les habitants relativement fortunés sont vêtus de bon drap et, malgré l’interdiction, de vêtements et accessoires de soie / The discovery in Tours of a set of almost 6000 pieces in the same pit, located just outside the city walls along the Loire River ("place Anatole France") provides an opportunity to study the entire process of textile work. The fragments studied are mostly wool cloth, which was a significant commercial production on the 15th - 16th centuries. As for remains of silk which are less well preserved, the study attempted to determine if they were produced in Tours. Among the shapes of wool remains, remarkably preserved, were a few clear parts of garments. Textiles were re-used to fashion laces and hoses in such a high frequency that the corpus is interpreted as the emptying of a second-hand clothes dealer shop. This corpus, combined with law texts regarding Tours, provides a picture of a late medieval capital city, where bourgeoisie wore good broadcloth and, contrary to law, silk dress accessories
215

Separação espermática pré refrigeração do sêmen equino / Sperm separation for cooling of equine sperm

Pessoa, Gilson Antonio January 2016 (has links)
As biotécnicas da reprodução na espécie equina avançaram na última década, tanto em conhecimento agregado por pesquisas como também pela demanda do mercado. No entanto, na espécie equina machos com subfertilidade são diagnosticados frequentemente com elevado número de espermatozoides com alterações morfológica e/ou imóveis. A utilização apenas de células viáveis para realizar o processo de resfriamento busca evitar perda de material (diluente) e produção de metabólitos tóxicos aos espermatozoides viáveis. O objetivo deste estudo foi utilizar a separação espermática (lã de vidro e centrifugação com Androcoll®) pré-resfriamento para incrementar a viabilidade do sêmen de garanhões pôneis refrigerados a 5ºC durante 48h. Os parâmetros motilidade, funcionalidade de membrana (HOST), viabilidade espermática (CFDA/PI), atividade mitocondrial e morfologia espermática foram avaliados no sêmen fresco e refrigerado (24 e 48h). A utilização da filtração por lã de vidro ou Androcoll® pré-resfriamento do sêmen equino selecionou espermatozoides com maior motilidade, funcionalidade de membrana, viabilidade espermática e atividade mitocondrial. Adicionalmente, a filtração por lã de vidro proporcionou refrigerar sêmen com elevado número de células morfologicamente normais sem perdas significativas de espermatozoides pelo processo de filtração. Tanto a técnica de lã de vidro como a centrifugação com Androcoll® mostraram-se eficientes em separar ejaculados com maior viabilidade para o resfriamento. Já a técnica de lã de vidro apresenta-se como uma técnica de baixo custo e de fácil execução para ser aplicada tanto para pequenos, ou grandes volumes de sêmen. / The reproduction biotechnologies in equine species have advanced in the last decade both in aggregate knowledge by research as well as the market demand. However, it in the equine species often with male subfertility where the ejaculate has a high number of sperm with morphological and / or property changes. The use of only viable cells to perform the cooling process seeks to avoid loss of material (diluent) and production of toxic metabolites to viable sperm. The aim of this study was to use the sperm separation (glass and spin wool with Androcoll®) pre-cooling to increase the viability of semen chilled ponies stallions at 5 ° C for 48 hours. We evaluated the motility parameters, membrane functionality (HOST), sperm viability (CFDA / PI), mitochondrial activity and morphology in fresh and chilled semen (24 and 48h). The use of filtration glass wool or Androcoll® pre-cooling of equine semen selected sperm with higher motility, functionality membrane, sperm viability and mitochondrial activity. In addition to filtration through glass wool afforded cooling semen with a high number of morphologically normal cells without significant losses of spermatozoids the filtration process. Both glass wool technique as centrifugation with Androcoll® were efficient in separating ejaculated more viability for cooling. Already glass wool technique presents itself as a low cost and simple technique to be applied to both small or large volumes of semen.
216

Concreto auto-adensável, de alta resistência, com baixo consumo de cimento Portland e com adições de fibras de lã de rocha ou poliamida / High strength self-consolidating concrete, with low content of cement Portland and addition of polyamide or rock wool fibers

Tobias Azevedo da Costa Pereira 28 April 2010 (has links)
O objetivo deste trabalho é apresentar uma metodologia que possibilita a obtenção de uma linha de concretos auto-adensáveis de alta resistência, econômicos e com reduzido impacto ambiental quando comparados com os concretos correntes. Para atingir estes resultados foram estabelecidos critérios de dosagem e de produção visando à sinergia entre os materiais constituintes do concreto. Foram pesquisados métodos de empacotamento dos agregados e adições minerais, estudada a interação entre o aditivo superplastificante e os materiais cimentícios e a incorporação de fibras de lã-de-rocha ou poliamida. Os concretos com matriz densa sob efeito de temperaturas elevadas tendem a sofrer lascamentos explosivos. Diante disso foi verificado o comportamento de corpos de prova e os resultados indicaram a importância da adição da fibra de poliamida nessa condição, onde o concreto resistiu a uma temperatura de 400ºC. Ensaios de resistência à abrasão indicaram que a fibra de lã-de-rocha melhora essa propriedade do concreto e, como esperado, essa adição não inibe o lascamento explosivo do concreto. Também foram determinadas as propriedades mecânicas dos concretos e concluiu-se que é possível o emprego de um concreto estrutural auto-adensável com consumo de cimento Portland da ordem de 325 kg/\'M POT.3\', fc7 = 53 MPa, fc28 = 71 MPa e Ec28 = 43 GPa. Devido à ação das adições minerais, estes concretos atingiram uma grande reserva de resistência à compressão após a idade de referência de 28 dias, obtendo-se 89 MPa aos 131 dias de idade. A densificação da pasta hidratada, a melhoria da zona de interface desta com os agregados, além da fissuração reduzida decorrente do baixo consumo de cimento e da adição de fibras indicam que este material tem desempenho superior ao prescrito pela NBR 6118 para as diversas classes de agressividade ambiental e de resistência. / The aim of this work is to show a methodology that allows to realize a set of high strength self-consolidating concrete, economic and with lower environmental impact when compared with current concretes. To get these results, criteria for production and mix design had been established aiming at to synergy between constituent materials of the concrete. Methods of particles packing (aggregates and mineral additions), the interaction between the superplasticizer and cementitious materials and the fiber incorporation were researched. The concretes with dense matrix under effect of high temperatures are susceptible to explosive spalling. In this situation, concretes were evaluated by testing cylindrical specimens and results evidenced the importance of the polyamide fiber when the concrete supported 400ºC. Tests of abrasion resistance indicated a good application for the wool-of-rock fiber, but this material not avoids explosive spalling. The mechanical properties of the concretes were determined and show that is possible to product a self consolidate concrete with low cement content (325 kg/\'M POT.3\'), fc7 = 53 MPa, fc28 = 71 MPa and Ec28 = 43 GPa. Due to action of the mineral additions, these concretes had a great reserve of compressive strength after the age of reference of 28 days and achieved 89 MPa at 131 days of age. The high density cement paste, the improvement of the matrix-aggregate interfacial zone and the reduced cracking due to the low cement content and the fibre addition indicate that these materials has superior performance to those prescribed for the NBR 6118 for diverse strength classes and aggressive environmental exposure.
217

Caracterização térmica de amostras de esponja sintética dupla face e palha de aço / Thermal characterization of synthetic sponge double sided and straw steel samples

Renata Aparecida Neres 31 October 2014 (has links)
Este trabalho tem por objetivo a caracterização comparativa do comportamento de degradação e/ou decomposição térmica da esponja sintética dupla face, base poliuretana (parte amarela e parte verde), e da palha de aço, a partir das técnicas termoanalíticas. As esponjas sintéticas para limpeza doméstica, em substituição à palha de aço, apesar da vantagem econômica, podem apresentar restrições de descartes para o meio ambiente ou expor o usuário a riscos de contaminação. Amostras de esponja sintética dupla face (verde e amarela) e de palha de aço foram caracterizadas por análise térmica (TG/DTG, DTA e DSC) empregando atmosfera dinâmica de ar e de N2. Essas amostras foram estudadas por métodos cinéticos por termogravimetria isotérmica e não isotérmica. Os parâmetros cinéticos obtidos permitiram estimar os tempos necessários para a decomposição de ambas as partes da amostra da esponja sintética e também da palha de aço sob atmosfera de ar. Os resultados evidenciaram claramente que a matriz polimétrica da esponja sintética para ser degradada completamente exige um tempo muito longo, acima de 20.000 anos. Por outro lado, os resultados indicaram comportamento similar entre as amostras de esponja sintética e de palha de aço considerando apenas o efeito temperatura e tipo de atmosfera. Contudo, no cotidiano sabe-se que a palha de aço se oxida muito facilmente sob atmosfera de ar na presença de umidade. / This work aims at a comparative characterization of degradation behavior and/or thermal decomposition of synthetic double-face sponge, polyurethane base (yellow part and green part), and steel wool, from thermoanalytical techniques. Synthetic sponges for household cleaning, replacing steel wool, despite the economic advantage, may have restrictions on discharges to the environment or expose the user to risks of contamination. Samples dual synthetic sponge face (green and yellow) and steel wool were characterized by thermal analysis (TG/DTG and DTA DSC) employing an atmosphere of air and N2. These samples were studied by kinetic methods isothermal and non-isothermal thermogravimetric analysis. The kinetic parameters obtained allowed the estimation necessary for decomposition of the sample both sides of the synthetic spomge and also of steel straw times under air atmosphere. The results clearly showed that polymetric matrix of synthetic sponge to be degraded completely requires a very long time, over 20,000 years. Moreover, the results showed similar behavior among synthetic sponge and steel wool sample considering only the effect of temperature and type of atmosphere. However, in daily life it is known that the steel wool oxidizes very easily under air atmosphere in the presence of moisture.
218

Etude de l'influence des transferts thermo-hydriques sur les composants d'assemblages bois sous incendie / Thermo-hydric transfer within dowelled and bolted timber connections under fire exposure

Samake, Abdoulaye 01 June 2016 (has links)
Les structures en bois sont de plus en plus utilisées de nos jours dans les constructions de génie civil. Cette utilisation massive du bois s’explique notamment par le caractère écologique du matériau et son attrait esthétique. Ces structures sont composées d’éléments en bois assemblés entre eux à l’aide d’organes métalliques tels que des boulons, broches, plaques métalliques,...etc. La résistance globale de la structure est étroitement liée aux capacités résistantes de ses liaisons. Ces zones constituent donc des endroits vulnérables lors d’un incendie. La compréhension de leur comportement sous sollicitation thermique de type incendie nécessite donc une attention particulière. Le bois est connu comme matériau anisotrope et relativement humide. La grande variabilité de ses propriétés mécaniques et la présence d’organes métalliques dans les assemblages rendent l’étude de ceux-ci beaucoup plus complexe. C’est notamment le cas en situation extrême d’incendie où la connaissance des valeurs de certains paramètres en fonction de la température est plus ou moins approchée. Lorsque l’assemblage est sollicité par des hautes températures, des flux thermiques et hydriques se manifestent et agissent sur les caractéristiques mécaniques et physiques des matériaux. Les méthodes actuelles de calcul technique de ces structures restent très sécuritaires et tendent à être simplificatrices dans certains cas. Une meilleure caractérisation de la réponse de ces assemblages sous action thermique s’impose si l’on veut optimiser les structures. Pour étudier les transferts thermiques et hydriques dans les éléments d’assemblages bois, deux approches ont été adoptées : expérimentale et numérique. L’approche expérimentale qui débute par l’étude d’un assemblage mono-tige soumis à l’action du feu ISO 834. L’étude des transferts thermiques à différents endroits des assemblages est réalisée ainsi que l’influence de la présence de la plaque métallique et le choix du type d’organes métalliques. Les résultats obtenus ont conduit à l’étude des deux éléments principaux de l’assemblage que sont le bois et les tiges métalliques. Les résultats obtenus permettent à la fois une meilleure compréhension et quantification de l’influence du choix de la tige métallique, de la présence de l’eau dans le bois. L’étude numérique a consisté à la mise en place de différents modèles. Un premier modèle simplifié basé sur les différences finies est réalisé. Il permet l’étude des transferts thermiques dans les organes métalliques. Ensuite deux modèles utilisant les éléments finis sont réalisés : le premier utilisé sous le code de calcul Msc.Marc et le second a été programmé ave des éléments finis surfaciques. Ce dernier modèle permet la prise en compte du comportement thermo-hydrique dans le matériau. Ils rentrent dans le cadre de la calibration des paramètres thermomécaniques du bois sous hautes températures et permettent d’aborder différentes configurations d’assemblages bois. Enfin une étude comparative et de discussion est réalisée entre les résultats réels et les résultats numériques. Les résultats obtenus sont satisfaisants. / Nowadays, timber structures are well on the way to democratization as regards building uses. They, indeed, present many advantages including light weight, speed of implementation and contribution to sustainable development. These structures are made of timber elements connected together using metal components such as bolts, dowels and nails forming the mechanical joints, which is sometimes reinforced with metal plates. Consequently, the joints are vulnerable areas when exposed to fire. Understanding their mechanical behavior, therefore, is essential, not only as regards fire exposure, but also as regards the coupling of the thermal and hydric fluxes within the connections. As we know, wood is an anisotropic material and relatively humid. The combination of the architectural demand and the material mechanical resistance requires wood materials to cohabit with other materials like steel fasteners. With the presence of steel members, thermo -hydric heat transfer phenomena within joints under fire exposure increase in speed and complexity [4 e7].This complexity comes from the difference between the materials regarding mechanical rigidity and thermo -hydric permeability. It affects the mechanical and thermo-physical properties of the materials eventually, in particular, thermal conductivity and specific heat subjected to the thermal action of fire. With this aim in view, the present research provides important experimental and numerical data, which are needed in the field of understanding and quantifying thermos-hydric transfer phenomenon within timber-steel connections. The objective of this thesis is to present the findings of the investigations carried out to study experimental and numerical thermo-hydric transfer of timber connections subjected to the ISO-834 standard conditions of fire exposure. The experimental part starts by the study of a sin gle bolt or single dowel timber-timber connections under fire. The temperature-time evolutions are measured at different places of the connections. Then two studies are carried out about the main two components of connections (wood and metal rods). The results obtained allow a good comprehension and quantification about the choice of the metal rods (bolt or dowel). A good comprehension is also obtained about the water contained in timber. The simulation model is reached in many ways: first, through the thermal study of the steel fasteners using the Finite Differences Method and another model using the Finite Element Method. Second, through the modeling of thermal behavior of the connection using the finite element method with the Msc-marc software is carried out. The last model is about the thermos-hydric behavior of the timber. The comparison between experimental and numerical results is satisfactory.
219

Investigation into non-aqueous remedial conservation treatments for iron-tannate dyed organic materials

Wilson, Helen Louise January 2013 (has links)
Iron-tannate dyes have been used for thousands of years and on many continents to colour materials that are now part of our cultural heritage shades of black, grey, or brown. Cellulosic and proteinaceous yarns and woven textiles have been dyed with iron-tannate dyes to form objects or components of objects for domestic and ceremonial use. Unfortunately, the longevity and useful lifetime of iron-tannate dyed objects is threatened by the dye itself which accelerates the degradation of organic materials through metal-catalysed oxidation and acid-catalysed hydrolysis. The accelerated degradation causes weakening, discolouration, and embrittlement of the organic materials at a faster rate than undyed equivalents and if left unimpeded, weakens the objects to the point that they are no longer able to be exhibited without damage. In some cases the degradation is so great that the dyed areas of the objects have crumbled to dust. At present there is no suitable chemical stabilisation method available with which to inhibit this degradation. An aqueous treatment is available for successfully stabilising paper containing iron gall ink; iron gall ink is chemically similar to iron-tannate dye. However, the aqueous nature of this treatment makes it unsuitable for weakened fibres, water soluble components, and water sensitive materials which may be part of a composite material containing iron-tannate dye. Non-aqueous treatments are therefore urgently needed in order to preserve our iron-tannate dyed cultural heritage for future generations.In this project a range of non-aqueous antioxidants and a non-aqueous deacidifier (described in Chapter 8) were tested alongside existing aqueous treatment in order to establish their ability to slow down the degradation of a range of model iron-tannate dyed textiles (Chapters 9 and 10). Model textiles were developed as part of the project (Chapters 3-5) to be substitutes for historic materials in these stabilisation studies. Validation of the model textiles for this purpose (Chapter 6) involved the comparison of the model textiles with selected historic iron-tannate dyed objects within the British Museum’s collection (Chapter 6). The historic objects and the properties of the model textiles before and after accelerated ageing (Chapters 5 and 6) and before and after treatment application (Chapters 9 and 10) have been characterised using a variety of analytical techniques (Chapter 2). In order to determine which accelerated ageing conditions were the most suitable for this project various combinations of elevated temperature and either cycling or stable relative humidity were tested for their ability to produce noticeable changes in the properties of the dyed model textiles within four weeks of ageing (Chapter 7). This project is an AHRC/EPSRC funded Science and Heritage Programme PhD in which the British Museum has been a collaborative institution. Among other wider dissemination methods, research from this project has been presented to the public on numerous occasions at gallery tours and Science Day events at the British Museum.
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Memento Mitten : Re-Collecting Human Hair as a Material

Ivarsson, Linnéa January 2020 (has links)
Memento Mitten is a project about seeing human hair from the perspective of sustainability as a viable alternative material. The project also aims to question our reluctance in Western Europe to use it in projects and innovations. It explores the process of transforming hair from waste into a functional piece (a mitten) by using traditional handicraft (hand carding, hand spinning and nålbinding) as a change agent in order to alter our perception of hair. Relating anthropologist Mary Douglas’ theory on dirt to the Freudian definition of ‘Das Unheimliche’ (The Uncanny) the project further examines and dissects the emotional aspects of Uncanniness and the anxiety we perceive when in contact with disembodied hair.  Leaning on Douglas’ theory on dirt I developed a framework for action that could potentially have the transformative ability to, when applied to creative practices, recontextualize hair from uncanny waste into an emotionally safe material. Utilizing auto-ethnographic documentation, physical exploration and participatory elements (through design interventions), four phases were identified: rejection (identifying hair as waste), re-collection (collecting hair), dissolution (taking apart the hair through acts like hand carding) and assimilation (putting the hair into a new context). These phases, which I titled The Altered Phases of Dirt, showed that they had the potential to move our inner margins of comfort beyond Uncanniness through the physical engagement found in handicraft.

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